Drescher Dennis G, Cho Won Jin, Drescher Marian J
Department of Otolaryngology, Wayne State University School of Medicine, Detroit, MI 48201, U.S.A.
Cell Biol Int Rep (2010). 2011;18(1). doi: 10.1042/CBR20110005.
Porosomes are proposed to be the universal secretory machinery of the cell plasma membrane, where membrane-bound secretory vesicles transiently dock and fuse to expel their contents to the extracellular space during cell secretion. In neurons, porosomes are manifested as cup-shaped lipoprotein structures in the presynaptic membrane, 12-17 nm in diameter and possessing a central plug. Hair cells of hearing and balance secrete transmitter from synaptic vesicles in sensory signal transduction, but it has not previously been demonstrated that these mechanosensory cells possess porosome structures that could participate in the secretory process. In the current study, we provide, for the first time, evidence obtained using transmission electron microscopy that porosome structures indeed exist in the hair cell, suggesting a mechanism of hair-cell transmitter secretion markedly different from that of the exocytotic process currently proposed.
孔体被认为是细胞质膜的通用分泌机制，在细胞分泌过程中，膜结合的分泌囊泡在此处短暂停靠并融合，以将其内容物排出到细胞外空间。在神经元中，孔体表现为突触前膜中的杯状脂蛋白结构，直径为12 - 17纳米，并有一个中央栓。听觉和平衡的毛细胞在感觉信号转导中从突触囊泡分泌递质，但此前尚未证明这些机械感觉细胞具有可参与分泌过程的孔体结构。在本研究中，我们首次提供了使用透射电子显微镜获得的证据，表明毛细胞中确实存在孔体结构，这提示了毛细胞递质分泌机制与目前提出的胞吐过程明显不同。
